The present disclosure relates to treatment of body tissues. More particularly, it relates to surgical systems, instruments, and methods useful in reducing and/or removing tumorous tissues.
Removal or reduction of body tissues is performed for a variety of reasons and on many types of tissues. For example, an organ may be removed upon its failure. In some cases, a tumor and/or surrounding tumor must be eliminated. Tumors are commonly treated with chemotherapy, radiation, surgery, and other techniques. When surgery is the treatment of choice, a variety of surgical instruments, such as a cavitational ultrasonic surgical aspirator (CUSA) or a surgical laser knife, are commonly used.
Brain surgery is the treatment of choice for accessible brain tumors. While a CUSA may be used to treat many tissues other than brain tumors, brain surgery provides a useful example to highlight some of the difficulties arising in the surgical removal of delicate tissues. The goal of surgery is to remove as much tumor tissue as possible. Among other procedures, the most commonly performed surgery for removal of a brain tumor is a craniotomy. In general, the neurosurgeon makes an incision into the scalp, cranium, dura, meninges, and cortex to expose an area of brain over the tumor. Location and removal of the tumor then takes place.
The delicate tissues associated with the human brain anatomy give rise to several concerns when using a CUSA, laser knife, or other brain surgery instruments such as cold steel instruments, ultrasonic cutting devices, and bipolar radiofrequency plasma ablation systems. By way of reference, the brain is covered by three membranes or meninges that in turn are surrounded by the skull. The three layers of meninges are the dura mater (immediately beneath the skull), the arachnoid, and the pia mater. Spinal fluid flows in the space between the arachnoid and the pia mater membranes, known as the subarachnoid space. These meninges are thin and delicate, with the pia mater carrying or maintaining the many blood vessels associated with the brain. Due to the friable nature of especially the pia mater, neurosurgeons must exercise great care when attempting to surgically remove a brain tumor; unintended damage to the pia mater can diminish the primary blood supply to the brain. Unnecessary injury to other healthy structures, such as the arachnoid or brain tissue (e.g., cerebral cortex) as well as unnecessary injury to cranial nerves and arteries supplying the brain (and brain stem) also can lead to patient impairment. With this in mind, CUSA instruments deliver ultrasonic action to remove tissue and bone. The surgeon attempts to place the ultrasonic cutting tip against tissue to be destroyed. However, high frequency cutting may also occur and damage tissue surrounding the targeted tumor when touched by the instrument's shaft. Further, due to the relatively large size of the CUSA handpiece, it may be difficult to visually confirm placement of the ultrasonic shaft/tip. Similarly, use of a laser knife may give rise to unintended tissue damage due to local heat in and around the incision line.
In another example, when treating of tumors and/or lesions in the airway great care also must be taken with delicate tissues, such as the vocal cords or the esophagus. For instance, lesions or tumors must be removed while sparing the surrounding mucosa to avoid scarring the vocal cords. In another instance, an overly aggressive resection of tissue in the airway can lead to a fistula involving the esophagus, which in turn can lead to aspiration of food and fluid.
In light of the above, surgeons and others continue to face the many challenges presented during reduction or removal of tumors and/or lesions while attempting to minimize normal tissue damage.